Terminal electrode of thin-film device with improved mounting strength, manufacturing method for the same, and thin-film magnetic head

Abstract

A terminal electrode provided on a lead joint of a thin-film device fabricated by a thin-film technology. The terminal electrode is constituted by an upper pad and a lower pad, the lower pad being formed into a pillar-like shape protuberantly projecting from the lead joint. The upper pad, which is wider than the lower pad, is formed on the lower pad such that the center thereof is aligned with the center of the lower pad. This arrangement provides the terminal electrode that allows a higher-density insulating layer free of defects, such as voids, to be formed around the terminal electrode, leading to an improved mounting strength of the terminal electrode.

What is claimed is:  
     
         1 . A terminal electrode of a thin-film device, the terminal electrode being provided on a lead joint portion of a thin-film device fabricated by a thin-film technology, comprising: 
 an upper pad; and    a lower pad,    wherein the lower pad is shaped like a pillar projecting from the lead joint portion, and the upper pad, which is wider than the lower pad, is formed on the lower pad such that the center thereof observed at least from one direction is aligned with the center of the lower pad.    
     
     
         2 . The terminal electrode of a thin-film device according to  claim 1 , wherein a lower insulating layer is formed around the lower pad such that it surrounds the lower pad and its front surface is flush with the upper end surface of the lower pad.  
     
     
         3 . The terminal electrode of a thin-film device according to  claim 1 , wherein an upper insulating layer is formed around the upper pad such that it surrounds the upper pad and its front surface is flush with the upper end surface of the upper pad.  
     
     
         4 . The terminal electrode of a thin-film device according to  claim 1 , wherein an electrode pad made of a precious metal is formed on the upper pad such that it covers the upper end surface of the upper pad and is electrically connected to the upper pad, and covers the upper end surface of the upper pad and adheres to the front surface of the upper insulating layer.  
     
     
         5 . A thin-film magnetic head comprising the terminal electrode according to  claim 1 .  
     
     
         6 . A manufacturing method for a terminal electrode formed of a lower pad and an upper pad and placed on a lead formed on a substrate, comprising: 
 a step of applying a resist on the substrate and the lead;    a step of forming a contact hole reaching the lead in the resist;    a step of forming a lower pad made of a conductive material to fill the contact hole;    a step of removing the resist after forming the lower pad;    a step of forming a lower insulating layer around the lower pad;    a step of planarizing the upper surface of the lower insulating layer and the upper surface of the lower pad; and    a step of forming an upper pad on the lower pad.    
     
     
         7 . The manufacturing method for a terminal electrode according to  claim 6 , wherein the lower pad is formed such that the conductive material filling the contact hole is not overflown out of the contact hole, and the upper surface of the lower pad and the upper surface of the lower insulating layer around the lower pad are planarized.  
     
     
         8 . The manufacturing method for a terminal electrode according to  claim 6 , wherein a second contact hole, which is wider than the lower pad, is formed in the resist at a position coaxial with the lower pad after a resist is applied to the planarized upper surfaces of the lower pad and the lower insulating layer, and the second contact hole is filled with a conductive material such that it does not overflow out of the second contact hole, thereby forming the upper pad.  
     
     
         9 . The manufacturing method for a terminal electrode according to  claim 6 , wherein, after the upper pad is formed, an upper insulating layer is formed to surround the upper pad, and an electrode pad made of a precious metal is formed on the upper pad and the upper insulating layer to cover at least the upper pad.  
     
     
         10 . The manufacturing method for a terminal electrode according to  claim 6 , wherein the electrode pad is formed such that it covers the upper surface of the upper pad, is electrically connected to the upper pad, and covers a part of the upper insulating layer around the upper pad.